Restrictions have reportedly been tightened on the extended family of the Chinese activist, Chen Guangcheng, at the center of a recent row between Washington and Beijing.

According to Chen, his lawyers, and human rights activists, Chen's brother and sister-in-law have been placed under house arrest, a nephew is in police detention, and several other relatives are facing restrictions on their movement in their village in Shangdong Province.

Chen fled house arrest in Shandong and into the protection of U.S. diplomats in Beijing, sparking a diplomatic row between Beijing and Washington.

Tensions eased after a deal was reached allowing Chen to study in the United States.